1. Field of the Invention
The present invention relates to a compensated, monolithic integrated Hall sensor comprising an integrated power supply device for operating currents. The invention further relates to a method for automatically compensating a Hall sensor for the production-induced sensitivity and the temperature dependence of the Hall element with and without a hysteresis switching device.
2. Description of the Related Art
Monolithic integrated Hall sensors are available commercially. In addition to being used to measure magnetic fields, monolithic integrated Hall sensors are increasingly employed where non-contacting switching is to be effected, such as, for example, in the field of rotational speed measurements in the gearing or tachometer area of automobiles. In such switch applications, the direction and magnitude of an alternating or unipolar magnetic field is determined by means of the Hall voltage, and when a threshold is exceeded, a count pulse is released. The electronic switch, which is represented, for example, by the open collector of a transistor, is, in most cases, part of the integrated circuit and, hence, part of the Hall sensor. For switch applications, Hall sensors generally include amplifying sensing elements or buffer amplifiers, Schmitt-trigger stages having hysteresis, and current-supply and/or voltage-supply devices.
A disadvantage of the known Hall sensors is that the compensation of the production variations in sensitivity and of the temperature dependence of the Hall element must be accomplished by individual adjustment steps during chip fabrication.
It is, therefore, the object of the invention as described and claimed herein to provide a circuit for a compensated Hall sensor, and to further provide a method underlying this circuit which permits automatic compensation of the technology-induced and temperature-induced variations in sensitivity without individual adjustment steps.